Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual IATA tem um ICAO de slk?
 ###Tabelas: CREATE TABLE airlines_based_in_changi (airlines_based_in_changi_id AUTO_INCREMENT PRIMARY KEY, Airline VARCHAR, IATA VARCHAR, ICAO VARCHAR, Callsign VARCHAR, Commenced operations INT) CREATE TABLE llws_results (llws_results_id AUTO_INCREMENT PRIMARY KEY, Year INT, Champion VARCHAR, City VARCHAR, LLWS VARCHAR, Record VARCHAR) CREATE TABLE college_career_statistics (college_career_statistics_id AUTO_INCREMENT PRIMARY KEY, Season VARCHAR, GP/MP VARCHAR, Kills INT, K/Game INT, Errors INT, Total Attempts INT, Percentage INT, Assists INT, Service Aces INT, Digs INT, Solo Blocks INT, Block Assists INT, Total Blocks INT, Points INT) CREATE TABLE world_energy_intensity_progression_by_year. (world_energy_intensity_progression_by_year._id AUTO_INCREMENT PRIMARY KEY, Country VARCHAR, Unit p koe/$05 VARCHAR, 2006 INT, 2007 INT, 2008 INT, 2009 INT) CREATE TABLE locomotives_of_the_early_period_for_all_types_of_train (locomotives_of_the_early_period_for_all_types_of_train_id AUTO_INCREMENT PRIMARY KEY, Class VARCHAR, Number(s) VARCHAR, Quantity VARCHAR, Year(s) of Manufacture VARCHAR, Type VARCHAR)  
SELECT IATA FROM airlines_based_in_changi WHERE ICAO = slk